Quincy Air Compressor Question

[MEngineer]

Hey there fellas (and ladies as the case might be) I need some wisdom.

I am looking at an Quincy QR-340 air compressor on CL for $350.

As of now, it has a 10hp 3phase motor which according to the seller is stuck. He is offering to throw in a 7.5hp 3phase motor for no additional cost. It is sitting on an approx 50-80 gal tank. It has spent the last 2ish years sitting behind his shop (came from his dad's estate) getting rained on in Washington.

From my brief reading of the Quincy manuals it would seem that the QR-340 does in the neighborhood of 17.5 cfm when being turned at optimal speed?

Anywho, now to my main questions:

1) is $350 a decent price for this?

2) can I put a smaller 1phase motor on it with a smaller pulley and just turn it slower? At this point, I have no need for 17.5 cfm, but I hope to in the future.

I figure that if I turn it slower, about 1/3 to 1/2 of the current pulley speed I would be getting somewhere between 6 and 9 cfm?

Your experience, failures, and knowledge would be helpful to avoid making my own new ones.

 

[930dreamer]

The tank condition is always the first unknown, short of having a hydro test done it's a **** shoot. A lot of threads about repowering with a single phase motor, any pics of the compressor?

 

[MEngineer]

 

[MEngineer]

 

[930dreamer]

WOW, that's a big pump and motor, I'm sure you know the tank isn't the original. If it were me I'd look for a gently used tank @ 80-120 gallons. 7.5-10hp single phase motors are expensive, any thought on building a rotary phase converter to produce three phase power?

If the pump can be rebuilt that is a great project, see if they will knock the price down because you can't see it run. It's missing the lines from the bottom of the head to the tank.

 

[On-Wheel]

That pump is missing the 2 stage air lines.See top of head on big pulley side.Its the cooling lines.I think that pump alone weighs 480 pounds.You could easily put a grand into it.Plus a tank.Thats guessing you don't need a crank,cylinder or head.I think it will do 200psi continuos. They'll run 24/7.Probably close to 5k for a new one that size.Its huge!You really need the ROC # to make sure parts are still available.Like on a 325 ROC 10 the oil pumps are obsolete and close to $800 for an updated one.
Edit looks like ROC21